Electrical issue

[DC105]

Greetings, i have followed this forum for a good while have never posted a question, because of all the good information that is available. So, here is my first. I have a 2007 club car gas with the 290 kawasaki motor. I backed it out of the garage and parked it while cleaning the garage. When to pull it back it and..... nothing, the solenoid clicks and the motors attempt to spin but voltage drops to the 9 volt category ( per the meter) and there is a loud humming coming from the motor. The motor actually spins about a quarter of a turn then stops and starts humming. I have a new solenoid and today took the starter off and bench tested it. It spins as it supposed to. Re installed everything with no change in function of cart . Looking for any suggestions of what to do next.

Thanks for anyone's advice